Optical microcavity

About: Optical microcavity is a research topic. Over the lifetime, 2599 publications have been published within this topic receiving 72125 citations. The topic is also known as: optical microcavities.

Spontaneous emission factor of a microcavity DBR surface-emitting laser

Abstract: The spontaneous emission factor (SEF) of a microcavity distributed Bragg reflector (DBR) surface-emitting laser has been obtained theoretically to investigate the possibility of the thresholdless lasing operation. Formulas expressing the spontaneous emission in a three-dimensional microcavity were obtained. By introducing the distribution of mode density in wavevector space, it is shown that the radiation pattern of spontaneous emission is deeply modified by the microcavity and is different from that in free space. Based on this result, the SEF and the emission lifetime are calculated as a function of emission spectral width and the size of the active region. It is found that the SEF exceeds 0.1, even though the spectral width is as large as 30 nm when the transverse size is smaller than 0.5 mu m and the DBR reflectivity is larger than 90%. >

Two-dimensional photonic bandgap defect laser

Abstract: We form a new type of optical microcavity using 2D photonic crystals embedded in a half wavelength thick waveguide Modes localized to a single defect in the photonic crystal can be theoretically shown to have small mode volumes The flexibility in design of the photonic crystal enables one to tailor the device for vertical emission or for coupling into an in-plane waveguide The added versatility in being able to etch the laser cavity may also help develop low threshold laser sources in material systems in which high index contrast epitaxial mirrors do not exist

Explanation of photon correlations in the far-off-resonance optical emission from a quantum-dot-cavity system.

Abstract: In a coupled quantum-dot–nanocavity system, the photoluminescence from an off-resonance cavity mode exhibits strong quantum correlations with the quantum-dot transitions, even though its autocorrelation function is classical. Using new pump-power dependent photon-correlation measurements, we demonstrate that this seemingly contradictory observation that has so far defied an explanation stems from cascaded cavity photon emission in transitions between excited multiexciton states. The mesoscopic nature of quantum-dot confinement ensures the presence of a quasicontinuum of excitonic transitions, part of which overlaps with the cavity resonance.

Photon statistics of semiconductor microcavity lasers.

Abstract: We present measurements of first- and second-order coherence of quantum-dot micropillar lasers together with a semiconductor laser theory. Our results show a broad threshold region for the observed high-beta microcavities. The intensity jump is accompanied by both pronounced photon intensity fluctuations and strong coherence length changes. The investigations clearly visualize a smooth transition from spontaneous to predominantly stimulated emission which becomes harder to determine for high beta. In our theory, a microscopic approach is used to incorporate the semiconductor nature of quantum dots. The results are in agreement with the experimental intensity traces and the photon statistics measurements.

Direct observation of correlations between individual photon emission events of a microcavity laser

Abstract: Coherent light emission in lasers is reflected in a change of the photon statistics. Here Wiersig et al. demonstrate a streak camera technique with sufficient time resolution to probe the dynamical evolution of correlations between individual photon emission events. This work may lead to novel quantum optical studies addressing the dynamics of correlation functions of light. Lasers are recognized for coherent light emission, the onset of which is reflected in a change in photon statistics; but, until now, attempts to directly measure correlations in the individual photon emission events of semiconductor lasers have been unsuccessful. By using a streak camera technique with sufficient time resolution, the dynamical evolution of correlations between individual photon emission events is now demonstrated. Lasers are recognized for coherent light emission, the onset of which is reflected in a change in the photon statistics1. For many years, attempts have been made to directly measure correlations in the individual photon emission events of semiconductor lasers2,3. Previously, the temporal decay of these correlations below or at the lasing threshold was considerably faster than could be measured with the time resolution provided by the Hanbury Brown/Twiss measurement set-up4 used. Here we demonstrate a measurement technique using a streak camera that overcomes this limitation and provides a record of the arrival times of individual photons. This allows us to investigate the dynamical evolution of correlations between the individual photon emission events. We apply our studies to micropillar lasers5 with semiconductor quantum dots2,3,6,7,8 as the active material, operating in the regime of cavity quantum electrodynamics9. For laser resonators with a low cavity quality factor, Q, a smooth transition from photon bunching to uncorrelated emission with increasing pumping is observed; for high-Q resonators, we see a non-monotonic dependence around the threshold where quantum light emission can occur. We identify regimes of dynamical anti-bunching of photons in agreement with the predictions of a microscopic theory that includes semiconductor-specific effects.